The invention relates to a fixture for drilling holes for and for making pocket hole joints in work pieces that are to be joined together.
A pocket hole joint is one that is used to join two work pieces, usually of wood, together by the use of a screw that is recessed. This type of joint is frequently used in making face frames, such as shown in FIG. 4, In which a rail R is to be joined to a stile S, with the two pieces being at a 90 degree angle to each other. As seen, a pair of angled pocket holes P are formed in one of the pieces, here shown as the rail, and a screw is driven though it into the other piece. The screws are recessed in the pocket holes and are not exposed.
The use of fixtures for location and guidance of a drill bit to drill a holes in a workpiece for a pocket hole joint is well known. U.S. Pat. No. 4,955,766 discloses the combination of a drill bit with a stop collar and a fixture used for making holes for a pocket hole joint in a workpiece. The fixture has an L-shaped base with the inner face of one leg of the base serving as a guide portion for the workpiece. The other base leg has a portion to hold a clamping device, shown as an over-center clamp, to hold the workpiece against the guide portion leg. An angled channel having a stop flange at its upper end is provided on the guide portion leg. The drill bit is inserted into the channel and drills a hole at an angle in the workpiece up to the point where the stop collar engages the flange. The fixture of this patent has no provision for holding together the two work pieces that are to be joined while the pocket holes are drilled.
U.S. patent application Ser. No. 09/517,253, filed Mar. 2, 2000, now U.S. Pat. No. 6,254,320, granted Jul. 3, 2001, which is assigned to the assignee of the subject application discloses a fixture having a U-shaped base for drilling holes for pocket hole joints. In this fixture one face of the workpiece is held by a screw clamp against the interior surface of a leg of the base having an angled guide channel that accepts a drill bit that is threaded on the opposing leg of the U-shaped base. An edge of the workpiece rests on the center, or support, leg having a channel into which the tip end of the drill bit can enter, with the channel being viewable from either end of the base. This fixture also is not capable of the drilling of the pocket holes with the two work pieces to be joined being held together.
A need exits for a fixture that can be used to hold the two work pieces together in the position in which they are to be joined while the angled pocket holes are being drilled and the screws are driven to fasten the pieces together.
The present invention relates to an improved and different form of a relatively simple fixture for making pocket hole joint holes in one workpiece while the other workpiece that is to be joined to it is held in the proper position for joining. In accordance with a preferred embodiment of the invention, a base for a toggle type clamp is fastened to a surface such as the end edge of a work table. A pocket hole drill guide member is mounted on a swivel at the end of the toggle clamp operating arm. The pocket hole drill guide has an angled guide channel for a drill bit with an exit opening.
A first workpiece, such as the stile of a face frame, is laid on the work table with one edge against a guide edge at the clamp base and the second workpiece, the frame rail, is butted at 90 degrees to the first piece. Actuation of the toggle clamp brings the pocket hole drill guide onto the top surfaces of both pieces to clamp them to the table. A drill bit is advanced in the guide channel of the drill guide to drill an angled pocket hole in the second piece and the drilled hole can extend into the first piece. The drill is removed from the drill channel and a screw is inserted in an driven through the guide channel to screw the second and first pieces together. The clamp is then released and the two joined pieces are removed from the table.
The pocket hole drill guide is preferably horizontally adjustable relative to the surfaces of the pieces that it engages to provide for selection of the position at which the pocket holes are to be drilled to accommodate work pieces of different widths. The drill guide also is preferably vertically adjustable to assure a firm placement of the pocket hole guide against the pieces being joined to clamp the to the table. This feature accommodates work pieces of different thicknesses. The fixture base can be permanently fastened to the work table, such as by using screws, or can be temporarily mounted, such as by use of a screw clamp. It also can be mounted on a rail so that it can be positioned along the length of the table.
In another embodiment of the invention the fixture has a clamp bar that extends vertically transverse to the work table. A lower clamp arm is mounted on the clamp bar that is to engage the lower surface of the work table. The first workpiece is placed on the table top surface aligned against the vertical clamp bar and the second piece is butted to it at 90 degrees. An upper clamp arm is mounted on the upper end of the clamp bar and the end of this arm extends above and over the two pieces on the work table. A pocket hole drill guide is mounted on a screw that is threaded into the upper clamp arm.
To operate the fixture of this embodiment, the clamp vertical bar serves as a guide for one edge of the first workpiece. The threaded clamp is screwed down until the pocket hole drill guide engages and is securely clamped to the top surfaces of the two work pieces. This holds and properly positions the pocket hole drill guide relative to the piece into which the pocket hole is to be drilled. Here also, the screw is driven through the guide channel of the drill guide into the angled pocket hole of the second piece and into the first piece.
In both of the embodiments the pocket hole drill guide can accept a conventional stepped drill bit or other suitable bit in the guide channel. The fixtures are relatively simple in construction and efficient in operation and permit precise drilling of pocket joint holes in one workpiece while another to which it is to be joined is held in clamped relationship so that the screw can be driven.
It is an object of the present invention to provide a novel fixture for drilling holes for pocket hole joints in one workpiece while another workpiece to which it is to be joined is held clamped to it.
A further object is to provide a fixture for clamping two work pieces to be joined to a table and for forming the holes for pocket hole joints in one workpiece and that permits the two pieces to be connected together by screws while they are still clamped to the table.
Another object is to provide a fixture for joining two work pieces by pocket hole joints in which a toggle clamp mounted on a base carries a pocket hole drill guide that engages and holds two work pieces together when the toggle clamp is actuated to permit drilling of angled pocket holes and driving screws to join the pieces.
Yet another object is to provide a fixture for joining two work pieces by pocket hole joints with the fixture being formed by a clamp bar that is to be located vertically transverse to the top surface of a work table on which the work pieces are placed, a lower clamp arm mounted on the bar to engage the lower surface of the worktable and a pocket hole guide mounted on movable member on a clamp arm at the upper end of the bar that is vertically adjustable to engage and clamp the work pieces to the table while the pocket holes are drilled.
A further object is to provide a fixture for drilling holes for pocket hole joints in which a pocket hole drill guide is moved into position from above the two work pieces on a table that are to be joined to clamp and hold them to the table while the pocket holes are drilled and the screws for joining the pieces are driven.